don't expect to see widespread use of metal detectors here at johns hopkins. the frightening news came shortly after 11:00. >> sounded chaotic, no one knew what was going on. >> reporter: thousands of hospital employees told there had been a shooting on the 8-t floor of the medical building, they locked themselves in not knowing where the gunman might beheaded. >> it's scary just knowing that someone is on the outside on a rampage. with a gun in a hospital where we're supposed to be protected. >> we contacted our mother, she had to hang the phone up abruptly -- >> it was only after securing the area and sending in s.w.a.t. teams that police learned the gunman, 50-year-old paul par advertise, had already shot himself and his mother inside of her hospital room. before that he had shot dr. david komen who had been informing him about his mother's condition. they initially thought it was warren davis. >> mr. davis removed a small semiautomatic handgun from his waist area, waistband area, and fired a single gunshot that struck the doctor in the lower chest/upper ab